X-Message-Number: 32183
Date: Sun, 29 Nov 2009 10:44:51 -0800 (PST)
Subject: cryoprotectant toxicity neutralization by quercetin I

[Quercetin eliminates DMSO induced toxicity, and greatly reduces glycerol
or ethanol induced damage. Quercetin also reduces cold storage-induced
renal injury, and possibly reduces ice crystal growth. However good
brain permeation would likely require liposome encapsulation. It is a
mystery why inexpensive quercetin does not see use in cryopreservation

Invest Ophthalmol Vis Sci. 2007 Aug;48(8):3714-8.
Responses of human lens epithelial cells to quercetin and DMSO.

Cao XG, Li XX, Bao YZ, Xing NZ, Chen Y. Department of Ophthalmology, People's 
Hospital of Peking University, Beijing, Peoples Republic of China.

    PURPOSE: Oxidative stress is an initiating factor in the development of 
    maturity-onset cataract. Diet has a significant impact on cataract 
    development, and individual dietary components responsible for the 
    protective effect include flavonoids, of which quercetin is the most 
    important. The purpose of this study was to investigate the protective 
    effect of quercetin and its toxicity for human lens epithelial cells 
    (HLECs). METHODS: HLECs in culture were incubated for 48 hours with either 
    1% (vol/vol) dimethyl sulfoxide (DMSO) alone or with this concentration of 
    DMSO and between 0.1 and 100 microM of quercetin. Nonstimulated cells served
    as control cultures. The viability of HLECs was measured by the 
    3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) 
    colorimetric assay. Gene expression was assessed with reverse 
    transcription-polymerase chain reaction (RT-PCR). Cellular apoptosis was 
    examined by in situ immunocytochemistry using terminal deoxynucleotidyl 
    transferase-mediated biotin-dUTP nicked labeling (TUNEL) and by flow 
    cytometry, using annexin V-FITC apoptosis detection. RESULTS: DMSO (1% 
    vol/vol) decreased cell viability, increased cellular apoptosis, and 
    upregulated Bax in these cells; 0.1 microM quercetin inhibited these effects
    and protected HLECs from the toxicity of DMSO. Higher concentrations of 
    quercetin the viability of HLECs decreased. In a dose-dependent response to 
    quercetin, cellular apoptosis increased and the change correlated with 
    upregulation of Bax and decreased cell viability. CONCLUSIONS: Quercetin, at
    a low concentration (0.1 microM), protects HLECs and reverses the toxic 
    effects of DMSO (1% vol/vol). However, at higher concentrations, quercetin 
    is toxic to HLECs with an LD(50) of 90.85 microM. Quercetin induced 
    apoptosis and upregulates apoptotic genes in HLECs in a dose-dependent 
PMID: 17652743

Brain Res. 1998 Jun 1;794(2):304-8.

Dimethyl sulfoxide, but not acidosis-induced metallothionein mRNA expression in 
neonatal rat primary astrocyte cultures is inhibited by the bioflavonoid, 

Conklin DR, Tan KH, Aschner M. Department of Physiology and Pharmacology, Wake 
Forest University School of Medicine, Winston-Salem, NC, USA.

    Metallothionein (MT) mRNA levels were analyzed following exposure of 
    neonatal rat primary astrocyte cultures to physiologic pH (7.4), acidosis 
    (pH 6.5 and 6.0), and dimethyl sulfoxide (DMSO). Treatments were carried out
    both in the presence and absence of the bioflavonoid, quercetin. Total RNA 
    was probed on northern blots with [alpha32P]dCTP-labeled synthetic cDNA 
    probes specific for rat MT isoform mRNAs. MT-I and MT-II mRNA levels in 
    astrocytes exposed to pH 6.5 or pH 6.0 were increased compared to controls 
    (pH 7.4). Treatment with DMSO in the presence and absence of acidosis, also 
    increased MT-I and MT-II mRNA levels compared to controls (pH 7.4). The 
    DMSO-induced increase in MT mRNA expression was reversed by treatment of 
    astrocytes with quercetin, such that MT-I and MT-II mRNA levels in DMSO plus
    quercetin-treated astrocytes were indistinguishable from mRNA levels in 
    their respective controls at pH 7.4, pH 6.5, and pH 6.0. These findings 
    suggest that both acidosis and DMSO exposure are associated with increased 
    astrocytic MT synthesis at the mRNA level, and that quercetin, effectively 
    blocks MT mRNA induction by DMSO. Copyright 1998 Elsevier Science B. V. All 
    rights reserved.
PMID: 9622659

Pharmacology. 2005 Jan;73(1):49-56. Epub 2004 Sep 27.

Reversal of experimental myoglobinuric acute renal failure in rats by quercetin,
a bioflavonoid.

Chander V, Singh D, Chopra K. Division of Pharmacology, University Institute of 
Pharmaceutical Sciences, Panjab University, Chandigarh, India.

    The occurrence of acute renal failure (ARF) following rhabdomyolysis has 
    been put at between 10 and 40% of cases, and accounts for between 3 and 15% 
    of all cases of ARF. Reactive oxygen intermediates have been demonstrated to
    play an etiological role in myoglobinuric renal failure. This study was 
    performed to explore the protective effect of quercetin, a bioflavonoid, in 
    an experimental model of myoglobinuric ARF in rats. Four groups of rats were
    employed in this study: group 1 served as control, group 2 was given 50% 
    glycerol (8 ml/kg, i.m.), group 3 was given glycerol + quercetin (2 mg/kg, 
    i.p.), and group 4 was given glycerol + DMSO (the solvent for quercetin, 5 
    ml/kg, i.p.). Renal injury was assessed by measuring serum creatinine, blood
    urea nitrogen, creatinine and urea clearance. The oxidative stress was 
    measured by renal malondialdehyde levels, reduced glutathione levels and by 
    enzymatic activity of catalase, glutathione reductase, and superoxide 
    dismutase. Glycerol administration resulted in a marked renal oxidative 
    stress, significantly deranged the renal functions as well as renal 
    cytoarchitecture. All these factors were significantly improved by quercetin
    treatment. Because of its radical-scavenging and iron-chelating properties,
    quercetin protected the kidney against the glycerol-induced oxidative 
    stress and resultant renal dysfunction. Based on these results, this study 
    confirms the role of oxidative stress and demonstrates the renoprotective 
    potential of quercetin in this rhabdomyolysis-mimicking model. 2005 S. 
    Karger AG, Basel.
PMID: 15452363

Am J Physiol Gastrointest Liver Physiol. 2009 Jun;296(6):G1318-23. Epub 2009 Mar

The protective role of HO-1 and its generated products (CO, bilirubin, and Fe) 
in ethanol-induced human hepatocyte damage.

Yao P, Hao L, Nussler N, Lehmann A, Song F, Zhao J, Neuhaus P, Liu L, Nussler A.
Universitatsmedizin Berlin, Charite, Campus Virchow, Department of General, 
Visceral, and Transplantation Surgery, Berlin, Germany.

    It has been reported that naturally occurring quercetin exerts 
    hepatoprotective effects through heme oxygenase-1 (HO-1) induction. However,
    the precise mechanism of how ethanol-associated liver damage is 
    counteracted by quercetin-enhanced HO-1 metabolism still remains unclear. To
    further decipher the protective role of quercetin on ethanol-induced liver 
    damage, we treated human hepatocytes with quercetin and various (end) 
    products of the HO-1 pathway. Our data clearly showed that quercetin 
    treatment attenuated ethanol-induced damage, whereas hemoglobin and zinc 
    protoporphyrin 9 (ZnPP) abolished such effects. Iron-II aggravated ethanol 
    toxicity and was only partially reduced by quercetin. In contrast, carbon 
    monoxide (CO) dose dependently inhibited ethanol-induced cytochrome P450 2E1
    (CYP 2E1) activity and hepatotoxicity but had no influence on CYP 2E1 
    protein expression. Similarly, hemoglobin dramatically stimulated CYP 2E1 
    activity but not the protein expression in quercetin- and ethanol-cotreated 
    hepatocytes. ZnPP significantly promoted CYP 2E1 protein expression in the 
    presence and absence of CO treatment but inhibited ethanol-induced CYP 2E1 
    activation following CO incubation in quercetin- and ethanol-cotreated 
    hepatocytes. These results suggested that quercetin virtually attenuated 
    ethanol-derived oxidative damage via HO-1 induction. Heme degradation and CO
    release may mediate the protective effects through inhibiting 
    ethanol-induced CYP 2E1 synthesis and enzymatic activity, respectively.
PMID: 19325051

World J Gastroenterol. 2008 May 28;14(20):3242-8.

Effects of quercetin on hyper-proliferation of gastric mucosal cells in rats 
treated with chronic oral ethanol through the reactive oxygen species-nitric 
oxide pathway.

Liu JL, Du J, Fan LL, Liu XY, Gu L, Ge YB. Department of Physiology, Nanjing 
Medical University, Nanjing 210029, Jiangsu Province, China.

    AIM: To investigate the effect of quercetin (3,3',4',5,7-pentahydroxy 
    flavone), a major flavonoid in human diet, on hyper-proliferation of gastric
    mucosal cells in rats treated with chronic oral ethanol. METHODS: Forty 
    male Sprague-Dawley rats, weighing 200-250 g, were randomly divided into 
    control group (tap water ad libitum), ethanol treatment group (6 mL/L 
    ethanol), quercetin treatment group (intragastric gavage with 100 mg/kg of 
    quercetin per day), and ethanol plus quercetin treatment group (quercetin 
    and 6 mL/L ethanol). Expression levels of proliferating cell nuclear antigen
    (PCNA) and Cyclin D1 were detected by Western blot to assay gastric mucosal
    cell proliferation in rats. To demonstrate the influence of quercetin on 
    the production of extra-cellular reactive oxygen species/nitrogen species 
    (ROS/RNS) in rats, changes in levels of thiobarbituric acid reactive 
    substance (TBARS), protein carbonyl, nitrite and nitrate (NOx) and 
    nitrotyrosine (NT) were determined. The activity of inducible nitric oxide 
    synthase (NOS) including iNOS and nNOS was also detected by Western blot. 
    RESULTS: Compared to control animals, cell proliferation in the gastric 
    mucosa of animals subjected to ethanol treatment for 7 days was significant 
    increased (increased to 290% for PCNA density P < 0.05, increased to 150 for
    Cyclin D1 density P < 0.05 and 21.6 +/- 0.8 vs 42.3 +/- 0.7 for PCNA 
    positive cells per view field), accompanied by an increase in ROS generation
    (1.298 +/- 0.135 micromol vs 1.772 +/- 0.078 micromol for TBARS P < 0.05; 
    4.36 +/- 0.39 mmol vs 7.48 +/- 0.40 mmol for carbonyl contents P < 0.05) and
    decrease in NO generation (11.334 +/- 0.467 micromol vs 7.978 +/- 0.334 
    micromol P < 0.01 for NOx; 8.986 +/- 1.351 micromol vs 6.854 +/- 0.460 
    micromol for nitrotyrosine P < 0.01) and nNOS activity (decreased to 43% 
    P<0.05). This function was abolished by the co-administration of quercetin. 
    CONCLUSION: The antioxidant action of quercetin relies, in part, on its 
    ability to stimulate nNOS and enhance production of NO that would interact 
    with endogenously produced reactive oxygen to inhibit hyper-proliferation of
    gastric mucosal cells in rats treated with chronic oral ethanol.
PMID: 18506933

Biol Pharm Bull. 2003 Oct;26(10):1398-402.

Quercetin, a flavonoid antioxidant, prevents and protects against 
ethanol-induced oxidative stress in mouse liver.

Molina MF, Sanchez-Reus I, Iglesias I, Benedi J. Department of Pharmacology, 
Faculty of Pharmacy, UCM, Madrid, Spain.

    This study evaluates whether quercetin (25, 50 and 75 mg/kg body weight) 
    treatment has a protective effect on the pro-oxidant-antioxidant state 
    following chronic ethanol treatment in mice. Pretreatment (quercetin 25, 50 
    and 75 mg/kg body weight for 15 d+co-treatment of ethanol 18%+quercetin for 
    15 d and ethanol 18% for the 15 d) increased the activities of superoxide 
    dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione 
    reductase (GR), and glutathione (GSH) in comparison to the ethanol group. No
    significant differences from the ethanol group were observed in the group 
    after post-treatment (ethanol 18% for 30 d+quercetin 25, 50 and 75 mg/kg 
    body weight for 15 d) with quercetin. A significant increase in lipid 
    peroxidation (malondialdehyde, MDA) products was observed in liver tissue 
    after administration of ethanol, which was attenuated by pre- and 
    post-treatment with a high dose of quercetin. GSH levels increased and 
    oxidized glutathione (GSSG) levels decreased in groups of ethanol-exposed 
    mice that received quercetin for 15 d prior to ethanol exposure. In 
    conclusion, pre-treatment of quercetin may protect against ethanol-induced 
    oxidative stress by directly quenching lipid peroxides and indirectly by 
    enhancing the production of the endogenous antioxidant GSH. There was no 
    protective effect on post-treatment with quercetin.
PMID: 14519943

Arch Toxicol. 2005 Jan;79(1):25-30. Epub 2004 Nov 4.

Oxidation of ethanol to acetaldehyde and free radicals by rat testicular 

Quintans LN, Castro GD, Castro JA. Centro de Investigaciones Toxicologicas 
(CEITOX) - CITEFA/CONICET, J.B. de La Salle 4397, B1603ALO Villa Martelli, 
Buenos Aires, Argentina.

    A large number of epidemiological studies evidencing that excessive alcohol 
    consumption is associated with impaired testosterone production and 
    testicular atrophy are available in the literature. One hypothesis to 
    explain the deleterious action of alcohol involves the in situ 
    biotransformation to acetaldehyde, but it strongly suggests the need to 
    learn more about the enzymatic processes governing alcohol metabolism to 
    acetaldehyde in different cellular fractions since limited information is 
    available in the literature. In this article we report studies on the 
    metabolic conversion of alcohol to acetaldehyde and to 1-hydroxyethyl 
    radicals in rat testicular microsomal fractions. The oxidation of ethanol to
    acetaldehyde in rat testes microsomal fraction was mostly of enzymatic 
    nature and strongly dependent on the presence of NADPH and oxygen. Several 
    compounds were able to significantly decrease the production of 
    acetaldehyde: SKF 525A; diethyldithiocarbamate; esculetin; gossypol; 
    curcumin; quercetin; dapsone; and diphenyleneiodonium. Microsomal 
    preparations in the presence of NADPH were also able to produce both 
    hydroxyl and 1-hydroxyethyl free radicals. Their generation was modulated by
    the presence of diphenyleneiodonium, gossypol, and deferoxamine. Results 
    show that rat microsomal fractions are able to metabolize alcohol to 
    deleterious chemicals, such as acetaldehyde and free radicals, that may be 
    involved in ethanol toxic effects. Enzymes involved could include CYP2E1, 
    P450 reductase, and other enzymes having lipoxygenase- /peroxidase-like 
PMID: 15526191

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